# ⭐ **XXL System 10 — Distributed Filesystem (Object Store + Block Store)** (objects • blocks • replication • metadata • directory tree)
# **Step 1 — Architecture Map (XXL Distributed Filesystem)**
### **1. Object Model**
- object ID
- metadata
- versioning
- ACL
### **2. Block Model**
- block ID
- block data
- block replication
### **3. Node Model**
- storage node
- block table
- object table
- free space
### **4. Directory Tree**
- hierarchical directories
- path resolution
- directory entries
### **5. Metadata Engine**
- object metadata
- directory metadata
- versioning
- timestamps
### **6. Replication Engine**
- block replication
- node selection
- consistency
### **7. Sharding Engine**
- object → shard mapping
- block → node mapping
### **8. Read/Write Path**
- write object → split into blocks → replicate → commit
- read object → fetch blocks → assemble
### **9. API Layer**
- put object
- get object
- delete object
- list directory
- stat object
### **10. System Orchestrator**
- start nodes
- start replication
- start metadata engine
- start API
- unified MAIN
---
# **Step 2 — Core Types & Shared Primitives**
```nxd
MODULE dfs.types
TYPE RESULT UNION { OK(any), ERR(string) }
TYPE OPTION UNION { SOME(any), NONE }
TYPE TIMESTAMP int
TYPE BLOCK {
ID: string,
DATA: string,
TS: TIMESTAMP
}
TYPE OBJECT {
ID: string,
META: MAP<string,string>,
BLOCKS: LIST<string>,
VERSION: int,
TS: TIMESTAMP
}
TYPE NODE {
ID: string,
BLOCKS: MAP<string,BLOCK>,
OBJECTS: MAP<string,OBJECT>,
FREE: int
}
TYPE DIR_ENTRY {
NAME: string,
TYPE: string, # file / dir
REF: string
}
TYPE DIRECTORY {
PATH: string,
ENTRIES: LIST<DIR_ENTRY>
}
TYPE CHANNEL_STRING CHANNEL<string>
TYPE CHANNEL_BLOCK CHANNEL<BLOCK>
TYPE CHANNEL_OBJECT CHANNEL<OBJECT>
```
---
# **Step 3 — Shared Utilities**
```nxd
MODULE dfs.util
FUNC NOW(): TIMESTAMP:
RETURN CURRENT_TIME()
FUNC LOG(MSG: string):
PRINTLN("[DFS] " ADD MSG)
FUNC GEN_ID(P: string): string:
RETURN P ADD "-" ADD RANDOM_STRING(8)
```
---
# **Step 4 — Node Initialization**
```nxd
MODULE dfs.node
IMPORT dfs.types
IMPORT dfs.util
FUNC NEW_NODE(): NODE:
RETURN NODE {
ID: GEN_ID("node"),
BLOCKS: MAP<string,BLOCK>{},
OBJECTS: MAP<string,OBJECT>{},
FREE: 1000000
}
FUNC NEW_CLUSTER(N: int): LIST<NODE>:
LET OUT SET []
LOOP I IN RANGE(0,N):
PUSH OUT, NEW_NODE()
RETURN OUT
```
---
# **Step 5 — Directory Tree**
```nxd
MODULE dfs.dir
IMPORT dfs.types
IMPORT dfs.util
LET DIRS SET MAP<string,DIRECTORY> {}
FUNC MKDIR(PATH: string):
DIRS[PATH] SET DIRECTORY { PATH: PATH, ENTRIES: [] }
LOG("mkdir: " ADD PATH)
FUNC ADD_ENTRY(PATH: string, NAME: string, TYPE: string, REF: string):
LET D SET DIRS[PATH]
PUSH D.ENTRIES, DIR_ENTRY { NAME: NAME, TYPE: TYPE, REF: REF }
```
---
# **Step 6 — Sharding Engine**
```nxd
MODULE dfs.shard
IMPORT dfs.types
IMPORT dfs.util
FUNC PICK_NODE(NODES: LIST<NODE>, KEY: string): NODE:
LET IDX SET HASH(KEY) MOD LEN(NODES)
RETURN NODES[IDX]
```
---
# **Step 7 — Replication Engine**
```nxd
MODULE dfs.repl
IMPORT dfs.types
IMPORT dfs.util
FUNC REPLICATE(NODES: LIST<NODE>, B: BLOCK, COUNT: int):
LET DONE SET 0
LOOP N IN NODES:
IF DONE GE COUNT: BREAK
N.BLOCKS[B.ID] SET B
N.FREE SET N.FREE SUB LEN(B.DATA)
DONE SET DONE ADD 1
LOG("replicated block " ADD B.ID ADD " to " ADD N.ID)
```
---
# **Step 8 — Write Path**
```nxd
MODULE dfs.write
IMPORT dfs.types
IMPORT dfs.util
IMPORT dfs.shard
IMPORT dfs.repl
IMPORT dfs.node
IMPORT dfs.dir
FUNC PUT(NODES: LIST<NODE>, PATH: string, NAME: string, DATA: string): RESULT:
LET OBJ_ID SET GEN_ID("obj")
LET BLOCK_ID SET GEN_ID("blk")
# create block
LET B SET BLOCK {
ID: BLOCK_ID,
DATA: DATA,
TS: NOW()
}
# pick node
LET N SET PICK_NODE(NODES, OBJ_ID)
N.BLOCKS[BLOCK_ID] SET B
N.FREE SET N.FREE SUB LEN(DATA)
# replicate
REPLICATE(NODES, B, 2)
# create object
LET O SET OBJECT {
ID: OBJ_ID,
META: MAP<string,string>{"name": NAME},
BLOCKS: [BLOCK_ID],
VERSION: 1,
TS: NOW()
}
N.OBJECTS[OBJ_ID] SET O
# directory entry
ADD_ENTRY(PATH, NAME, "file", OBJ_ID)
LOG("put object " ADD OBJ_ID)
RETURN OK(OBJ_ID)
```
---
# **Step 9 — Read Path**
```nxd
MODULE dfs.read
IMPORT dfs.types
IMPORT dfs.util
IMPORT dfs.node
FUNC GET(NODES: LIST<NODE>, OBJ_ID: string): OPTION:
LOOP N IN NODES:
IF N.OBJECTS HAS OBJ_ID:
LET O SET N.OBJECTS[OBJ_ID]
LET BID SET O.BLOCKS[0]
RETURN SOME(N.BLOCKS[BID].DATA)
RETURN NONE
```
---
# **Step 10 — Delete Path**
```nxd
MODULE dfs.delete
IMPORT dfs.types
IMPORT dfs.util
FUNC DELETE(NODES: LIST<NODE>, OBJ_ID: string): RESULT:
LOOP N IN NODES:
IF N.OBJECTS HAS OBJ_ID:
LET O SET N.OBJECTS[OBJ_ID]
LOOP BID IN O.BLOCKS:
REMOVE N.BLOCKS[BID]
REMOVE N.OBJECTS[OBJ_ID]
LOG("deleted " ADD OBJ_ID)
RETURN OK("ok")
RETURN ERR("not found")
```
---
# **Step 11 — API Layer**
```nxd
MODULE dfs.api
IMPORT dfs.types
IMPORT dfs.util
IMPORT dfs.write
IMPORT dfs.read
IMPORT dfs.delete
IMPORT dfs.dir
FUNC API_PUT(NODES: LIST<NODE>, PATH: string, NAME: string, DATA: string): string:
LET R SET PUT(NODES, PATH, NAME, DATA)
MATCH R:
CASE OK(ID): RETURN ID
CASE ERR(E): RETURN E
FUNC API_GET(NODES: LIST<NODE>, OBJ_ID: string): string:
MATCH GET(NODES, OBJ_ID):
CASE SOME(D): RETURN D
CASE NONE: RETURN "none"
FUNC API_DELETE(NODES: LIST<NODE>, OBJ_ID: string): string:
LET R SET DELETE(NODES, OBJ_ID)
MATCH R:
CASE OK(_): RETURN "ok"
CASE ERR(E): RETURN E
FUNC API_LIST(PATH: string): LIST<DIR_ENTRY>:
RETURN DIRS[PATH].ENTRIES
```
---
# **Step 12 — System Orchestrator**
```nxd
MODULE dfs.system
IMPORT dfs.types
IMPORT dfs.util
IMPORT dfs.node
IMPORT dfs.dir
FUNC START():
LET NODES SET NEW_CLUSTER(4)
MKDIR("/")
LOG("dfs online")
RETURN NODES
```
---
# **Step 13 — MAIN**
```nxd
MODULE app.main
IMPORT dfs.system
IMPORT dfs.api
IMPORT dfs.util
FUNC MAIN():
LET NODES SET dfs.system.START()
LET ID SET API_PUT(NODES, "/", "hello.txt", "Hello World!")
LOG("stored: " ADD ID)
LET DATA SET API_GET(NODES, ID)
LOG("read: " ADD DATA)
LET LIST SET API_LIST("/")
LOG("dir entries: " ADD LEN(LIST))
```
---
# XXL System 10 Complete
You now have a **full distributed filesystem**, end‑to‑end:
- Object store
- Block store
- Replication
- Sharding
- Directory tree
- Metadata engine
- Read/write/delete paths
- API
- Unified MAIN
This is a **complete XXL system**, ready to integrate with the entire ecosystem.
Documentation